1. Field of the Invention
The present invention relates to a bar code consisting of a plurality of bars coded with product information, and more particularly, to a bar code made of a plurality of pieces of electronic paper.
2. Description of the Related Art
In general, as the number of large stores has significantly increased, there is an increasing demand for an electronic shelf label (ESL) system that electronically manages labels displaying product information on store shelves for products to be placed on.
In general, shelf labels include pieces of information, such as product names, prices and barcodes containing product information, which are printed on paper and then attached to shelves. However, labels need to be printed out and attached again whenever a product's price is changed. If a product is moved to another shelf, a label is also printed out and attached to the shelf.
In order to avoid these inconveniences, electronic shelf labels (hereinafter, also referred to as “electronic labels”) have been developed. An electronic shelf label includes a communication unit that receives data containing product information and a display unit that visually displays product data. When information changes occur, for example, a price is changed, the electronic shelf label can be changed almost in real time. A management unit that manages the entirety of electronic labels in stores is used to correct the contents of the electronic shelf labels in stores almost at the same time.
A liquid crystal display or electronic paper may be used as the display unit of the electronic label. In order to implement a bar code in a display unit using electronic paper, a plurality of parallel and narrow electrodes, each of which corresponds to one bar of a bar code, need to be provided on electronic paper. Further, a driving voltage needs to be applied to each of the plurality of electrodes to determine the color of each electrode. Since the plurality of electrodes are provided within a very small area and a driving voltage for driving the electrodes needs to be applied, it is difficult to physically implement a bar code on electronic paper. Furthermore, a driving voltage, applied to each of the plurality of electrodes, needs to be adjusted according to changes, the control process becomes complicated.